What's an excellent example of tips integrated on a web page?Are you sure you even need these? I'm a big advocate of getting rid of tool-tips and the like altogether. Either fix the problem that requires the tooltip in the first place, or consider making the copy you see on the screen explain things better so that you don't need a secondary bit of content.

Readability of overlaid text on imagesThis is a graphic design question more than a UX question. I'd suggest it be migrated to GD. As for an answer to the question, asking if there is a consensus on a rather subjective topic is going to be tough.